The Influence Of The Flow Electrification On The Corrosion In The Oil Delivery Pipeline

Pipelining is one of the main transportation ways for modern oil products,because of its some advantages in economy,convenience,continuity,etc.However,due to the causticity of oil products and the complexity of pipeline laying environment,the pipelines will be easily corroded,which will influence the transmission efficiency and pipeline safety.For decreasing the pipeline corrosion,some researches on the anticorrosive material and technology have been carried out in recent years,and some new materials,new technologies and new equipment have been widely used.Pipeline corrosion mainly includes electrochemical corrosion and chemical corrosion There are various factors on the corrosion,but the influence of the flow electrification phenomenon at the pipeline-oil interface on corrosion is scarcely studied.In the paper,the corrosion mechanism of the oil pipeline has been stated,the causes of the corrosion have been analyzed and the effective protection measures also have been put forward.And particular attention is focused on the discussion of the influence of the electric properties of the pipeline wall caused by the formation and separation of the electric double layer on the pipe corrosioa This provides a new research direction and theoretical basis for the cornosion and protection,and all of these provide a substantial basis for the safety of pipeline operation under the current production conditions and have an important guiding significance to protong the service life of pipeline.In this paper,by using aqueous solutions and insulating oil as the liquid flow medium,we investigated the effect of static charge generated by the friction between different mediums and ppeline on the corrosion of pipeline,the conclusions were as follows:(1)When the medium contacted with the metal pipe,an electric double layer was formed on the interface due to the different properties of the solid and the liquid surfaces;when the relative motion occurred between them,the electric double layer was separated and the metal surface was charged.(2)The leakage current and voltage increased with the increase of the flow rate.when the metal pipe was grounded,and the measured values were different with various mediums flowing through the pipe.(3)When the flow rate changed in the different flow states,the changes of current and voltage in turbulence with the rising flow rate were greater than that of laminar flow.(4)The current and voltage generated in the case of installing the electric charge trapper was smaller than that of without the trapper.This was because some electric charge in the oil bulk were caught by the trapper and then conducted to be neutralized with the opposite charge of equal amounct on the metal pipe surface.(5)When the metal pipewas grounded,the generated leakage current would accelerate the pipeline corrosion,and the greater the leakage current was,the greater the impact on the Pipeline corrosion was.